Test tube carrier

ABSTRACT

The invention relates to a test tube carrier ( 4 ) for transporting test tubes in a transport system, said carrier ( 4 ) comprising a base ( 8 ) having a recess made thereto for accommodating the bottom of a test tube/vial ( 1 ), and support members ( 9, 10 ) adapted to the carrier base ( 8 ) for clamping a test tube ( 1 ) inserted in said recess and supporting the same. The support members ( 9, 10 ) are permanently affixed to said carrier base ( 8 ) and comprise elongated portions with their free ends bent toward the vertical center axis of the carrier base and said upper ends providing a support surface ( 22 ) for making supportive contact to the test tube. The bottom of the carrier base recess for accommodating a test tube is advantageously made flat and the carrier base is provided with test tube support members whose support surfaces ( 22 ) extend to at least two different heights from the top level of the carrier base ( 8 ).

[0001] The invention relates to a test tube carrier according to thepreamble of claim 1 for transporting different kinds of test tubes insample analysis systems and other kinds of automatic specimen handlingsystems, wherein individual test tubes/vials are moved between separatestations.

[0002] These kinds of test tube carriers are conventionally used fortransporting samples to be analyzed for probing at different analyzerstations. The sample transport system comprises a conveyor lane formoving the transport carriers and a number of carrier handling points,wherein the carrier with its test tube(s) can be moved to a sampleprobing point, a queue thereof or to a buffer station, for instance. Thetest tube carrier is provided with grooves and projections thatsupportingly mate the edges of the transport track so as to guide thetravel of the carrier and secure its upright position. The travel of thetest tubes is controlled by means of a bar code attached to the tubes,whereby the bar code must be readable at all handling stationsirrespective of the tube and carrier positions.

[0003] A test tube carrier of the above-described kind is disclosed inCanadian Patent Application No. 2,216,052 related to a specimentransport system. The test tube carrier described in the publication hasa central recess made to the round carrier base having thereaboutadapted retainer members of thin, round steel wires that project uprightfrom the base at the sides of the recess. The bottom end of a test tubeis placed in the recess, whereby the steel-wire retainer members supportthe test tube from its sides. The lower end of the steel-wire retainermembers supporting the test tube is bent in a Z-shape so that one end ofthe bent wire is inserted into a hole made in the carrier base, whilethe other end forms an upright oriented portion that supports the testtube. The lower end of the steel wire inserted in the hole of thecarrier base is adapted freely rotatable in the hole and theupright-oriented portion of the wire is adapted in an arcuate controlgroove that guides the movement of the wire. The carrier base generallysupports three steel-wire retainer members that are displacedsymmetrically about the recess of the base. Below the tips of theupright-oriented portions of the steel-wire retainer members is adaptedan O-ring serving to squeeze the wires toward the vertical center axisof the carrier base so that the wires are forced to follow the arcuateshape of the control groove while their lower ends rotate in the holesof the carrier base. When the test tube is inserted in the carrier, thesteel-wire retainer members are urged apart from each other, and, havingthe test tube in place on the carrier, the O-ring clamps the steel-wireretainer members against the test tube.

[0004] The above-kind of test tube carrier, however, is hampered byplural disadvantages. Due to incorporating loosely moving members,difficult-to-clean recesses that may accumulate sample material andother impurities are formed, e.g., in the holes and control grooves ofthe steel-wire retainer members of the carrier base. As a result, thestructure has a higher need for aggressive washing and disinfection,whereby the washing step becomes extremely arduous especially for theO-ring that must be replaced from time to time due to aging. If thecompressive force exerted by the ring is lost or the ring breaks up, thetest tubes will not stay upright at all on the test tube carrier. If thetest tube flips aside during transport, the moving carriers contaminatethe transport system over a large area, whereby a long shutdown isnecessary for cleaning. Hence, the condition of the carriers must becontinuously monitored during the operation of the transport system. Themachining of the drilled holes and arcuate control grooves need twocutting steps per each steel-wire retainer member and, furthermore, anunnecessarily complicated casting mold for making the carrier base. Theuse of elongated steel-wire retainer members adapted to conform with theexterior surface of a test tube is also hampered by the problem of thewire members supporting the test tube only at one point unless the wiremembers are made extremely flexible. These support points do not readilycoincide with each other at the same height of the test tube, wherebythe test tube assumes a tipped position under the forces imposed theretoat the support points located at different heights. This problem can beovercome by shaping a conical or concave bottom for the recess drilledto the carrier base, whereby the shape of the recess bottom supportssufficiently the bottom end of the test tube with the penalty of havingtest tubes of the different size placed at different heights and makingsample recovery and reading of identification information moredifficult. If the retainer members are made from a material of such ahigh elasticity that the compressive force imposed by the O-ring canpress them along their entire length against the exterior surface of thetest tube, the wires generally become so thin that the risk of damagethereto in the insertion and removal of test tubes becomes substantial.Inasmuch the lower ends of the steel-wire retainer members and theirdrilled support holes must be located close to the periphery of thecarrier base, the base must be made high, because the transport systemguide grooves of base cannot be located within the portion of thecarrier base occupied by the holes drilled for the retainer members. Asa result, the transport system guide grooves of the carrier base must bemade to the bottom portion of the base, wherein they give inferiorguidance to the travel of the test tube carrier than if the guidegrooves were located at a higher elevation from the bottom portion ofthe test tube carrier.

[0005] It is an object of the present invention to provide a test tubecarrier featuring secure support to test tubes inserted into apredetermined position and having no loosely moving members.

[0006] The goal of the invention is achieved by way of adapting in afixed fashion to the sides of the carrier base recess such elasticmembers that offer a support surface for a test tube insertedtherebetween.

[0007] According to a preferred embodiment of the invention, the testtube carrier has made thereto a flat-bottom recess for accommodating atest tube and there are two elastic members adapted above one another sothat their support surfaces are located at different levels from thecarrier base.

[0008] More specifically, the test tube carrier according to theinvention is characterized by what is stated in the characterizing partof claim 1.

[0009] The invention offers significant benefits.

[0010] A test tube carrier according to the invention has no looselymoving parts, whereby its wear in use and need for maintenance areminimal. As the structure has no loosely moving parts, it can bedesigned free from any recesses or holes capable of accumulatingcontaminating material. Accordingly, the test tube carrier is easy toclean and keep in a hygienic condition. The test tube carrier operatesproblem-free at all times and possible damage in its structure isinstantly visible. The base part of the test tube carrier can bemanufactured advantageously by injection molding without any need forpost-machining, and the device is extremely simple to produce by manualtechniques or in automatic assembly systems. The test tube carrieroperates reliably over a large range of test tube/vial sizes and thebottom of the recess made in the base part thereof for supporting thetest tube bottom can be flat, whereby the test tube/vial will assume atall times an equal height and a correct alignment guided by the elasticsupport members. The elastic support members can be advantageously madefrom spring steel band, whereby they become sufficiently stiff forholding test tubes in a reliable fashion. The location of the elasticsupport members does not curtail the degree of freedom in the shaping ofthe exterior surface of the carrier base part thus allowing the guidegrooves to be made deeper in order to reduce the swaying of the carrierduring its travel. The elastic support members cope with test tubes ofvarying dimensions and shapes as allowed within their manufacturingtolerances so as to keep the test tubes firmly gripped by the elasticsupport members.

[0011] In the following, the invention will be examined in greaterdetail with the help of exemplary embodiments illustrated in theappended drawings in which

[0012]FIG. 1 shows a test tube carrier according to the invention in itsoperating environment;

[0013]FIG. 2 shows a perspective view of the embodiment of FIG. 1; and

[0014]FIG. 3 shows a cross-sectional view of the embodiment of FIG. 2.

[0015] Referring to FIG. 1, therein is shown a portion of a transportsystem suited for moving test tubes 1 placed on test tube carriers 4between different handling stations. The transport system comprises aguide lane 3 forming a transport path for the test tube carriers 4 andhaving rails 2 at its sides for supporting the test tube carriers duringtheir travel and preventing the same from tipping aside. At the bottomof the guide lane 3 are provided running belts 5 (not shown) on whichthe test tube carriers move supportedly. The guide lane 3 forming thetransport path controls the transport route of a given test tube carrier4. Operating along the path of the guide lane are adapted handlingstations capable of performing analysis of a sample contained in a testtube, rearrangement of the sample sequence and other possible functionssuch as derouting to a crossing lane. In the transport system of FIG. 1,the handling station shown therein includes a turnstile disc 7 with atransfer slot 6 for receiving a test tube carrier 4. The test tubecarrier 4 has a rotation-symmetric shape that mates with the compatibleshape of the transfer slot. When a test tube carrier 4 comes to thehandling station, the carrier meets a transfer slot 6, whereby it can bepicked off from the lane by means of rotating the disc 7 to an analyzerfor instance. Simultaneously, the solid periphery of disc 7 preventssuccessive test tube carriers from passing forward during the time thetransfer slot is rotated off from lane 3. As the function and structureof the transport system is not essentially related to the presentinvention, its detailed description need not be discussed furtherherein.

[0016] In FIGS. 2 and 3 is shown an embodiment of the test tube carrier4 according to the invention. This kind of test tube carrier is intendedfor use in conjunction with test tubes of dia. 10 to 17 mm. The testtube carrier comprises a base 8 with elastic support members 9, 10affixed to the base. The base 8 has a rotation-symmetric shape and hasits lower portion and upper portion provided with glide faces 11, 12adapted to supportedly mate with the edges of the transport system guidelane 3. Above the lower glide face 11 is located a guide groove 13 thatmates with the shape of the guide rails 2 of transport system guide lane3. Above the guide groove 13 is first made a narrow face 14 for opticindicia and then above the narrow face 14 is located an upper glide face12. Obviously, the exterior design of a test tube carrier according tothe invention is not limited by the exemplary embodiment describedherein, but rather, the actual contour of the test tube carrier must bemade compatible with the structure of the transport lane. The base 8 ofthe test tube carrier is formed by two parts, namely, an outer shell 14and a cup part 15 adapted to fit therein. The bore of the outer shell ismachined to so as have a recess whose interior diameter is smaller thatthe inner rim portion of the outer shell 14 extending to the top levelof the outer shell 14, whereby a shoulder 16 is formed into the outershell bore. The outer rim of the cup part 15 is made compatible withthis shape of the outer shell bore so that the cup part has a larger rimportion 17 fitting snugly in the large-diameter portion of the outershell bore. The center recess bore of the cup part 15 has a straightcylindrical inner wall with a flat bottom. In a ready-assembled testtube carrier, these two parts are put together concentrically so thattheir top rims are in the same plane. In practice, these parts can bemade from polymer materials by injection molding, for instance. Since,the test tube carrier is not subjected to major mechanical stress, itmay also be fabricated from any other easy-to-clean material.

[0017] In a side view, the elastic support members 9, 10 resemble theshape of a fishing hook. Typically, the support members are made fromstainless steel band or any similar elastic and durable material. Eachelastic support member comprises a single contoured strip having a righthand angle bend 18 made to its one end. To the opposite end of themember in regard to bend 18 is contoured a smooth arc so that the stripterminates at a finger portion 19 directed toward the right-angle bend18 and at its end an inward hook tip 20 pointed toward the insidesurface of the finger portion. The convex edge of the hook tip acts as asupporting surface 22 that rests against the periphery of an insertedtest tube/vial, and this convex edge surface is advantageously orientedin a direction perpendicular to the center axis of the test tube and thevertical center axis of the base, whereby it will form a point-likecontact to the round surface of the test tube periphery. The upper set10 of elastic support members is made longer than the lower set. Thespring function of these elastic support members 9, 10 is provided bythe resilience of the long straight portion 21 between the bent portionsand the long bend of the finger portion. In this fashion the straightportion can be made longer by having the finger portion 19 bent downwardtoward the carrier base 8.

[0018] In the illustrated embodiment, the number of elastic supportmembers 9, 10 is eight, whereby they are superposed pairwise above oneanother in two concentric circles at 90° spacing from each other. Thesuperposed support members are placed inside one another so that theshorter member 9 is innermost thus aligning the hook portions of members9 and 10 above one another in the vertical direction. The outer surfaceof the cup part 15 of the carrier base is provided with grooves suitedto accommodate the elastic support members and having at the ends of thegrooves recesses suited to accommodate the right-angle bent end 18 ofthe elastic support members 9, 10. In the assembly of the test tubecarrier, the elastic support members 9, 10 are first inserted in thegrooves of the cup part, whereupon the cup part 15 with its elasticsupport members is pressed into the bore of the outer shell 14 tocomplete the assembly. The seam between the outer shell 14 and the cuppart 15, as well as the root of the elastic support members is securedwith a sealant, for instance, whereby the test tube carrier is finishedfree from any crevices capable of accumulating contamination and thelocking of the carrier members to each other is assured. Resultingly,the elastic support members become an integral part of the test tubecarrier. During the assembly step, between the outer shell 14 and thecup part 15 is placed a so-called RFID tag memory chip that can receivethe identification data of the test tube specimen over a radio-frequencylink and then provide the read-out of the data at any time so desired.

[0019] Without departing from the scope and spirit of the presentinvention, embodiments different from those described above may becontemplated.

[0020] For instance, the carrier body could be made from several parts,but this option only makes its manufacture more complicated andcostlier. The number of elastic support member pairs may be varied from3 to 5, in certain applications up to 6 pairs, with the penalty that thegreater number of elastic support members may complicate the read-out oftest tube/vial identification indicia, such as a bar code, by automaticdetection means. If the bottom of the carrier base is provided with aconical or concave recess, it is feasible to use only one elasticsupport element instead of a pair of support members in each supportmember position, whereby a test tube/vial inserted in a carrier issupported by said conical recess and only one ring of the elasticsupport elements. This arrangement, however, eliminates the benefitachievable by the flat bottom of the test tube recess in the carrier.The elastic support elements need not necessarily be placed interposedwith each other, but if the support members are staggered about theperiphery of the carrier base, difficulties will be encountered in thereadout of test tube indicia and assembly of the test tube carrier.Obviously, the elastic support elements do not necessarily have adownward directed hook portion, but their free ends may as well bedirected first toward the vertical center axis of the carrier base andthen upward. The hooked tip may be bent outwardly at the upper end ofthe support member or, alternatively, coiled into a ring. The end of theelastic support elements facing the test tube/vial is advantageously.shaped so as to provide at the contact point a horizontally linealsupport surface 22 that makes only a point-like contact to the peripheryof the test tube, whereby the support given thereto becomeswell-defined. However, this kind of a straighter support member lackingthe hooked portion offers less elasticity with the same band materialthickness and makes the of the support member tips look sharper whichmay give a less user-friendly impression. While the elastic supportelements are advantageously made in the above-described fashion from aflat band material, also other continuous sections such as tubularblanks may be contemplated as the raw material of the elastic members.

What is claimed is:
 1. A test tube carrier (4) for transporting testtubes in a transport system, said carrier (4) comprising a base (8)having a recess made thereto for accommodating the bottom of a testtube/vial (1), and support members (9, 10) adapted to the carrier base(8) for clamping a test tube (1) inserted in said test tube recess andsupporting the same, said support members (9, 10) being permanentlyaffixed to said carrier base (8) and comprising elongated portions withtheir free ends bent toward the vertical center axis of the carrier baseand said upper ends providing a support surface (22) for makingsupportive contact to the test tube, characterized in that the supportsurface (22) of said support members is arranged to extend to at leasttwo different heights from the top level of the carrier base (8).
 2. Thetest tube carrier of claim 1, characterized in that the bottom of saidtest tube recess is flat.
 3. The test tube carrier of claim 1,characterized in that the bottom of said test tube recess is providedwith a downward tapering portion.
 4. The test tube carrier of any one offoregoing claims, characterized in that the upper end of said supportmembers (9, 10) include a hooked finger portion (19, 20) directed towardthe vertical center line of the carrier base and then toward the carrierbase (8).
 5. The test tube carrier of claim 4, characterized in thatsaid support members (9, 10) are made from a flat band material.
 6. Thetest tube carrier of claim 4 or 5, characterized in that said supportsurface (22) forms a horizontally lineal contact surface alignedperpendicular to the center axis of the test tube (1).
 7. The test tubecarrier of any one of foregoing claims, characterized in that thecarrier base (8) is assembled from two concentrically insertable parts(14, 15) leaving therebetween recesses into which the lower ends of saidsupport members (9, 10) are permanently affixed.